Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria
By 2022, Bulgaria’s National Reference Laboratory had confirmed 4024 HIV cases. We analyzed 132 pol gene sequences to characterize the molecular epidemiology of HIV-1 subtypes A1, A6, and A7 (2001–2022). A1 accounted for 50.0% (66/132) of cases, increasing after 2014, with peaks in 2019 and 2022. A6...
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2025-05-01
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| author | Aleksandra Partsuneva Anna Gancheva Reneta Dimitrova Lyubomira Grigorova Asya Kostadinova Maria Nikolova Radoslava Emilova Nina Yancheva Rusina Grozdeva Ivailo Alexiev |
| author_facet | Aleksandra Partsuneva Anna Gancheva Reneta Dimitrova Lyubomira Grigorova Asya Kostadinova Maria Nikolova Radoslava Emilova Nina Yancheva Rusina Grozdeva Ivailo Alexiev |
| author_sort | Aleksandra Partsuneva |
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| description | By 2022, Bulgaria’s National Reference Laboratory had confirmed 4024 HIV cases. We analyzed 132 pol gene sequences to characterize the molecular epidemiology of HIV-1 subtypes A1, A6, and A7 (2001–2022). A1 accounted for 50.0% (66/132) of cases, increasing after 2014, with peaks in 2019 and 2022. A6 comprised 48.5% (64/132), dominating from 2005 to 2014 before stabilizing. A7 was rare (1.5%, 2/132), detected in 2003 and 2011. Transmission patterns varied: A1 was linked to men who have sex with men (MSM) (62.1%), while A6 was primarily heterosexual (HET) (82.8%) with a balanced gender distribution (56.3% male, 43.8% female). Resistance mutations were identified in 29.6% of cases, with A6 showing higher rates of nucleoside reverse transcriptase inhibitor (NRTI) (20.3%) and non-nucleoside reverse transcriptase inhibitor (NNRTI) (7.8%) resistance than A1. Phylogenetic analysis revealed that 13 Bulgarian sequences (9.8%) were involved in transmission clusters, including 10 (7.6%) from sub-subtype A1 and 3 (2.3%) from sub-subtype A6, highlighting distinct genetic diversity and transmission patterns. Despite significant migration from Ukraine in 2022, A6 prevalence remained unchanged, suggesting localized transmission dynamics. These findings highlight a shifting HIV-1 sub-subtype distribution in Bulgaria and emphasize the need for targeted prevention, diagnosis, and treatment strategies tailored to the evolving molecular landscape. |
| format | Article |
| id | doaj-art-eefeb48089a44e328ee12c4c09a4b1e7 |
| institution | OA Journals |
| issn | 2076-2607 |
| language | English |
| publishDate | 2025-05-01 |
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| series | Microorganisms |
| spelling | doaj-art-eefeb48089a44e328ee12c4c09a4b1e72025-08-20T01:56:42ZengMDPI AGMicroorganisms2076-26072025-05-01135110810.3390/microorganisms13051108Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in BulgariaAleksandra Partsuneva0Anna Gancheva1Reneta Dimitrova2Lyubomira Grigorova3Asya Kostadinova4Maria Nikolova5Radoslava Emilova6Nina Yancheva7Rusina Grozdeva8Ivailo Alexiev9National Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Laboratory of Immunology, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaNational Reference Laboratory of Immunology, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaSpecialized Hospital for Active Treatment of Infectious and Parasitic Diseases, 1606 Sofia, BulgariaSpecialized Hospital for Active Treatment of Infectious and Parasitic Diseases, 1606 Sofia, BulgariaNational Reference Confirmatory Laboratory of HIV, National Center of Infectious and Parasitic Diseases (NCIPD), 1504 Sofia, BulgariaBy 2022, Bulgaria’s National Reference Laboratory had confirmed 4024 HIV cases. We analyzed 132 pol gene sequences to characterize the molecular epidemiology of HIV-1 subtypes A1, A6, and A7 (2001–2022). A1 accounted for 50.0% (66/132) of cases, increasing after 2014, with peaks in 2019 and 2022. A6 comprised 48.5% (64/132), dominating from 2005 to 2014 before stabilizing. A7 was rare (1.5%, 2/132), detected in 2003 and 2011. Transmission patterns varied: A1 was linked to men who have sex with men (MSM) (62.1%), while A6 was primarily heterosexual (HET) (82.8%) with a balanced gender distribution (56.3% male, 43.8% female). Resistance mutations were identified in 29.6% of cases, with A6 showing higher rates of nucleoside reverse transcriptase inhibitor (NRTI) (20.3%) and non-nucleoside reverse transcriptase inhibitor (NNRTI) (7.8%) resistance than A1. Phylogenetic analysis revealed that 13 Bulgarian sequences (9.8%) were involved in transmission clusters, including 10 (7.6%) from sub-subtype A1 and 3 (2.3%) from sub-subtype A6, highlighting distinct genetic diversity and transmission patterns. Despite significant migration from Ukraine in 2022, A6 prevalence remained unchanged, suggesting localized transmission dynamics. These findings highlight a shifting HIV-1 sub-subtype distribution in Bulgaria and emphasize the need for targeted prevention, diagnosis, and treatment strategies tailored to the evolving molecular landscape.https://www.mdpi.com/2076-2607/13/5/1108HIV-1subtype A1subtype A6subtype A7molecular epidemiologyphylogenetic analysis |
| spellingShingle | Aleksandra Partsuneva Anna Gancheva Reneta Dimitrova Lyubomira Grigorova Asya Kostadinova Maria Nikolova Radoslava Emilova Nina Yancheva Rusina Grozdeva Ivailo Alexiev Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria Microorganisms HIV-1 subtype A1 subtype A6 subtype A7 molecular epidemiology phylogenetic analysis |
| title | Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria |
| title_full | Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria |
| title_fullStr | Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria |
| title_full_unstemmed | Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria |
| title_short | Distinct Molecular Epidemiology, Transmission Patterns, and Resistance Mutations of HIV-1 Subtypes A1, A6, and A7 in Bulgaria |
| title_sort | distinct molecular epidemiology transmission patterns and resistance mutations of hiv 1 subtypes a1 a6 and a7 in bulgaria |
| topic | HIV-1 subtype A1 subtype A6 subtype A7 molecular epidemiology phylogenetic analysis |
| url | https://www.mdpi.com/2076-2607/13/5/1108 |
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